Lead scavenger compositions



United States Patent 2,819,156 LEAD SCAVENGER COMPOSITIONS Venard E. Yust, Alton, and John L. Barrie, East Alton,

lll., assignors to Shell Development Company, Emeryville, Califi, a corporation of Delaware No Drawing. Application March 10, 1953 Serial No. 341,616

15 Claims. (CI. 44-69) This invention relates to compositions which are useful as scavengers with lead anti-knock compounds. I

The use of lead compounds in gasolines to increase the octane ratings thereof is extremely Widespread. There are, however, several rather serious adverse effects which accompany the use of leaded 'gasolines. One of these elfects, the deposition of various lead compounds within the combustion chambers of the engines, has been at least partially remedied by the use 'of halohydrocarbon scavengers such as ethylene dibromide. Another adverse effect, which has been attributed to the lead anti-knock compounds, is misfiring of the engine due to spark plug fouling. This spark plug fouling is quite prevalent under conditions of high temperature engine operation and, particularly in the case of aircraft engines, is a very serious type of trouble.

It is therefore, an object of the present invention to overcome the previous shortcomings arising from the use of leaded gasolines. Itis a further'object to provide novel scavenger compositions for use with lead anti-knock compounds and in gasoline fuels. Another object is to pro vide novel fuel compositions containing said scavenger compositions. Another object is to provide novel compounds for the above and other uses. Other objects will be apparent hereinafter.

It has now beenfound that theme, as a lead'scavenger in leaded gasoline fuel compositions, of a mixture of a halohydrocarbon scavenger andof a smaller amount of a hydrocarbyl-substituted alicyclic derivative of a chalcogenide, including oxide, sulfide, selenide, and telluride or a hydride of arsenic, antimony or bismuth, will result in greatly improved operation of sparkignition internal combustion engines. More particularly, the use of such scavenger'acompositions substantially eliminates spark plug fouling, or at least minimizes such fouling toa point where it is no longer a material consideration in engine'operation. This outstanding/advantage is obtained without having the other necessary characteristics (such as stability, performance rating, etc.) of the fuel deleteriously affected to any material degree by the presence of the scavenger compositions.

The arsenic, antimony andbi'smuth compounds of the present invention will be referred to hereinafter as antifouling compounds or"anti-fouling agents.

The halohydrocarbon scavenger which makes up the major proportion of the scavenger compositions of the present invention may 'be, for example, any one or more of the numerous halogen scavenger compounds already known, such as ethylene dibromide and ethylene dichloride (U. S. 2,398,281), acetylene tetrabromide (U. S. 2,490,606), hexachloropropylene, monoand polyhalo propanes, butanes and pentanes (U. S. 2,479,900 and U. S. 2,479,902), polyhalo-alkylbenzenes (U. S. 2,479,901

and U. S. 2,479,903), and the like, having a volatility between about 100 and about 0.1 mm. Hgat 50 C.

In general, the most effective anti-fouling agents of the present invention :are a class of new compounds containing an element having an atomic number of at least propyl groups, is very advantageous.

33, exhibiting a valency of three or five, and being selected from group V-B of the periodic table as presented in Paulings General Chemistry (1948, Freeman & Co), and including in said molecule at least one hydrocarbylsubstituted alicych'c radical connected directly by a carbcn atom thereof or indirectly through only one intervening non-carbon atom to the element having an atomic number of at least 33, preferably through an atom of a bivalent non-metallic element having an atomic number of at least 8, namely oxygen, sulfur, selenium, or tellurium, oxygen and sulfur being preferred. The hydrocarbyl radicals attached directly by carbon-to-carbon linkage or indirectly through only one intervening non-carbon atom to the alicyclic radical can be the same or diiferent alkyl, alkenyl, aryl, alkaryl, aralkyl, etc. Alkyl radicals having a total of not more than 15 carbon atoms are generally preferred, those with less than 5 carbon atoms in the allcyl chain being preferable.

The essential alicyclic group required in the present anti-fouling agents is a cyclic group,-preferably monocyclic group of non-aromatic character. Alkyl (andother aliphatic hydrocarbon) groups containing a total up to about 12 or 15 carbon atoms, substituted upon'the 'alicyclic groups markedly increase the anti-fouling effectiveness of the present anti-fouling compounds. A multiplicity of such substitutions, e. g., two or three methyl, ethyl or While substituents other than hydrocarbon radicals do not, in general, adversely affect the efficiency of compounds of this invention as anti-fouling agents, it is preferred that the substituent groups be unsubstituted hydrocarbyl radicals.

A preferred class of the above compounds is the hydrocarbyl-substituted cyclic derivatives of the hydrides, oxides and sulfides of arsenic, namely, alicyclic hydrocarbon arsines, arsenates, arsenites, thioarsenates, thioarse' nites, arsonates, etc.

Compounds of this invention can be readily prepared without recourse to any special equipment or technique. Thus, the full or partial esters of arsenic, antimony or bismuth can be prepared by treating the appropriately substituted cycloalkanols with halides of arsenic, anti' mony or bismuth. The alcohols can be prepared by conventional means such as by hydrogenation of substituted cyclic ketones, hydrogenation of substituted phenolic compounds or aromatic mercaptan's, or by catalytic hydrogenation of suitable carboxylic acids such as described in U. S. Patents 2,105,664 and 2,328,719.

For example, arsine compounds of this invention can be prepared from a hydrocarbyl-substi'tuted cycloalkanol or the mercapto analogs by replacing the OH or -SH group with a halogen such as by the action of halogen acids so as to form the hydrocarbyl-substituted alicyclic halide. This material in turn can be treated with a Grignard reagent to form the hydrocarbyl-substitute-d.alicyclic metal salt (Q) -RMX wherein Q is one'or more hydrocarbyl substituent radicals, R is the alicyclic radical; M is an active metal, e. g., Mg; X is a halide and y is-an integer of at least 1 and preferably about 3. This salt is then treated with a halide of arsenic, antimony or bismuth to form the new productof this invention.

Suitable alicyclic alcohols for use as starting materials in the preparation of compounds of this invention include cycloalkanols, such as cyclopentanols, cyclopenten'ols, cyclohexanols, cycloheptanols, cyclohepte'nols, bicycloheptanols, etc. Specific compounds are 3,3,5-trimethyl'cyclohexanol, 4,6-ditertiarybutyI-Z-methylcyclohexanol, borneol, isoborneol, abietyl alcohol, cycloalkanols produced by hydrogenation of isophrone and isophrone bottoms as described in Adelson Patents 2,481,487 and 2,502,408 as well as cycloalkenols described in U. S. Patents 2,433,008, 2,467,451, 2,493,733, 2,497,349, 2,574,077 and 2,597,843;

A particularly preferred compound, tris( 3,3,5 -trimethylcyclohexyl) arsine, was prepared by treating 3,3,5-trimethylcyclohexanol with HBr to form 3,3,5 -trimethylcyclohexyl bromide. About 3 moles (636 g.) of the bromide was refluxed in an ether medium with about 78 g. (3.2 moles) of magnesium in the presence of iodine. The Grignard thus formed was reacted with about 0.4 mole of A501 at about zero degrees centigrade in an ether solution. The ether layer was separated and filtered and thereafter the ether was flashed off leaving a residue, which by analysis is representable by the formula CH3 CH3 namely, tris(3,3,5-trimethylcyclohexyl) arsine.

Following the above procedure but using 4,6-ditertiarybutyI-Z-methylcyclohexanol as starting alicyclic alcohol, tris(4,6-ditertiarybutyl 2 methylcyclohexyl) arsine was prepared.

Tris(3,3,5-trimethylcyclohexyl) arsenite was prepared by refluxing 3,3,5-trimethyleyclohexanol with an excess of AsCl in an ether medium.

Tris(3,3,5-trimethylcyclohexyl) arsenate was prepared by refluxing 3,3,5-trimethylcyclohexanol with an excess of AsCl in an ether medium.

Other specific illustrative and representative compounds of this invention and which compounds are particularly suitable for use as anti-foulants in hydrocarbon fuels, such as aviation gasoline, are: tris(3,3,5-triethylcyclohexyl) arsine, tris(4,6-ditertiarylbuty1-3-methyl-cyclohexyl) arsine, di(p-dodecylcyclohexyl) arsine, di(p-heptylcyclohexyl arsine, 2-octyl-3,S-dimethylcyclohexyl arsine, tris(3,5,5-trimethylcycloheptyl) arsine, tris(Z-methylcyclopentyl) arsine, phenyl 3,5 dimethylcyclohexyl arsine, allyl-3,5-dimethylcyclohexyl arsine, naphthyl 2,5-diethylcyclohexyl arsine, laurylcyclohexyl diphenyl arsine; tris(3,3,5-trimethylcyclohexyl) arsenite, tris(3,5,S-triethyl-cyclohexyl) arsenite, B-methylcyclohexyl di-p-toluene arsenite, Z-allyleyclopentyl dibenzene arsenite, tris(3,3,5-trirnethylcyclohexyl) arsenate, tris(2,4-dimethylcyclopentyl) arsenate, tris(3,5,5-tributylcyclohexyl) arsenate, 3-butylcyclohexyl dibutyl arsenate, Z-butylcycloheptyl diphenyl arsenate, tris (3,3,5-trimethylcyclohexyl arsonate, di(2-ethylcyclohexyl) benzene arsonate, tris(3,3,5-trimethylcyclohexyl) stibine, 3,3,5 trimethylcyclohexyl stibine, 3,3,5 trimethylcyclohexyl arsine oxide, 3,3,5-triethylcyclohexyl arsine oxide, 3,3,5 trimethylcyclohexyl arsine sulfide, 2 methylcyclohexyl bismuthine, 3methylcyclo hexane arsonous acid, 2,4-dibutylcycloheptane arsenic acid, and the corresponding analogs of the antimony and bismuth compounds.

The arsenic, antimony and bismuth compounds of this invention can be supplied to the combustion zone of the engine in various ways to accomplish reduction in fouling of spark plugs due to the combustion of leaded fuels there in. Thus, they can be injected directly into the combustion zone, separately from either or both the fuel and the anti-detonant, or injected directly and separately into the intake manifold, either intermittently or substantially continuously, as desired, or they can be incorporated with the leaded fuel. They can be added separately to the leaded fuel, or they can be blended first with either the gasoline or the anti-detonant; in the latter case, an antidetonant, scavenger and anti-foulant concentrate is suitably prepared which can be stored and shipped as such and blended with the gasoline as desired.

The following are illustrative examples of compositions suitable for use according to the present invention:

Example I Tetra-ethyl lead 1.0 theory ethylene dibromide 0.2 theories tris(3,3,S-trimethylcyclohexyl) arsine 4 Example H Tetra-ethyl lead 1.0 theory ethylene dibromide 0.1 theory trimethylcyclohexyl bismuthine Example III T etra-ethyl lead 1.0 theory ethylene dibromide 0.1 theory p-octyl dimethylcyclohexyl stibine oxide Example IV Tetra-ethyl lead 1.0 theory acetylene tetrabromide 0.4 theory methylcyclohexyl dibenzene arsinate Example V octane aviation gasoline containing, per gallon 0.5 cc. tetra-ethyl lead 1.0 theory ethylene dibromide 0.2 theory trimethylcycloheptyl stibine 0.02 gr. 2,4-dimethyl-G-tertiary-butylphenol Example VI Aviation alkylate containing, per gallon 4.6 cc. tetra-ethyl lead 1.0 theory ethylene dibromide 0.04 gr. 2,4-dimethyl-6-tertiary-butylphenol 0.1 theory tris(3,3,5-trimethylcyclohexyl) arsenate Example VII Tetra-ethyl lead 1.2 theories hexachloropropylene 0.2 theory tributylcyclohexyl bismuthine Example VIII Tetra-ethyl lead 0.8 theory ethylene dibromide 0.2 theory trimethylcyclohexyl arsine sulfide Example IX Tetra-ethyl lead 1.5 theories hexachlorobutadiene'lfi 0.1 theory tris(3,3,S-trimethylcyclohexyl) arsenite Example X Example XI grade aviation gasoline containing, per gallon 4.6 cc. tetra-ethyl lead 1.0 theory ethylene dibromide 0.2 theory tributylcycloheptyl bismuthine 004 gr. 2,4-dimethyl-6-tertiary-bntylphen0l Example XII Tetra-ethyl lead 0.5 theory ethylene dibromide 0.1 theory methycyclohexyl di-p-toluene arsenite Example XIII Tetra-ethyl lead 0.8 theory ethylene dichloride 0.2 theory allyl di(methylcyclohexyl) stibine sulfide Example XIV Tetra-ethyl lead 1.0 theory ethylene dibromide 0.1 theory trimethylcyclohexane arsonous acid Example XV Motor gasoline containing, per gallon 1.6 cc. tetra-ethyl lead 1.0 theory hexachlorethane 0.2 theory allyl di(trimethylcyclohexyl) arsine 0.06 gr. N-butyl-p-aminophenol xampl VI straa hxllsad :9 h yleneibmm e ull ys qh x in oxide 1 Example XVIII iat azstlwk sad htbsqt lstby s'ae d bwmide t t a .nhenr i itlauu c opemy .sfibine Example XIX I Tetra-ethyl-lead 10-thoryethylene dichloride I 0.; theory di-(m-tolyl)dihithylcyclohexane arsonate fi ml le X 'Ietra-ethyllead 1:0 theoryethylene dibromide 0.1 tlieoryflijethy'l thylcycloheptyl stibine vEl lt lll X I Tetra-sauteed 1.0 ryethylene .dibromide "-10. 551 Y th k ql hcxylar en t xampl XXIII Tett -at x ile s J l sg sthyl ne .dihr niide "-1 mean -g m hylcy penty a i e 1 Ex m l X V Tetra ethyl lead 1:0 "th'ofy'efliylcne dibromide t 613?i thtlttalqh ar na a Exam l XXV Ta azq hrll a sae ib mi s Bz QFYlSiiQfli/lQYQl MXYl) Sabi As already indicated, the order of mixing the various constituents iof'the' 'p'rese'nt composition's'i's immaterial. For example, theanti-fouling compound may be added to a gasoline which alre dy Contains the anti-hnock'compound and halog eif' scavii'ger'. Likewise, the metalld-organic anti-knock agent, the halogen-scavenger and the "antifoulifig 'ir'omp'ouiid ma be firstmiked, stored and handled as a carienfrtejana added to the'gasoline ata later'tirne. A typical concentrate of thislatter type has approximately theffollowing' composition? Weightpercent Tetra-ethyl lead v "SS-{6O Ethylene" diurognd -30 Tris(3;3:5-ttiniethylcyclohexyl) arsine 10-15 Kerosene, inhibitor, dye stabilizer, etc 3-6 Under-other circumstances it may be desirable to mix the halogen scavenger andthje anti-fouling agents, or the nthlmaka ntandlh .a r cn i agent, i h desir d and handle or store this mixture,

ela ive. atsasuisas.

' out stabilizers, inhibitors, etc., as a concen- Wi or i tion the other components of sir-intimate Whey y gfi ga #1 retiring-agar] I about 1.5 theories, based upon the lead content of the gasblinejbift ayadvantageouslybe as low as'0.4 or as hi'gli'iis'lfl'ih some cases." The preferred range is from about 0.9 to about l l theories.

ger compositions of the present unt of halogen scavenger plus anti;

will generally r511 between about 0.6

The ratio of,the. two components oflthe scavenger com= position is rather important. For example, if theproportion of halogenscavenger present is too large, exce ssive wear and corrosion of certain.operatingparts such asexhaust valves and valve guides, is noted. Iftootsmalla quantity of halogen scavenger is .used, the lead deposits are not effectively scavenged. Iftoo small av quantityof the anti-fouling compound is used, the sparkplug fouling will not bematerially reduced; and if too much of that compound is present the amounts of deposits andthe plug fouling both may be increased. In general, ,the;the,ory ratio of the halogen scavenger or scavengers vto theanti fouling agents should be between about 3:2 andahout :1. For best results this ratio should be .between about 2:1 and about 15:,1. As an additionallimitation, the total scavenger mixture and the ratio of components therein should be adjusted so that the anti-fouling compound is present in an amount of between about .0.01.and about 0.6 theories, and preferably between about 0.1 and about 0.2 or if desired between about 0.05 .and about 0.4 theories. A particularly desirable composition comprises 1 theory of the halogen scavenger and 0.1 theory of the anti-fouling compound. It is to be understood that more than one of the oompoundsfrom each class (i. e. halogen scavenger or anti-fouling agent), may be used in any single composition, just so the total quantity of each type falls withinthe limits set forth above.

The term theory, when used in conjunction with a halogen scavenger compound, designates the amount of scavenger required to react stoichiometrical-ly with a given amount of lead :anti-detonant so that allot the lead atoms and all of the halogen atoms form PbBr or PbCl In other words, a theory of scavenger is an amount which contains two atomic proportions of halogen for each atomic proportion of lead in the anti-detonant, or, a theory of the halohydrocarbon scavenger is one mol of the halohydrocarbon scavenger divided by one-half the number'of halogen atoms per molecule, for each gram atom otlead in the lead anti-detonant present, and therefore, the number of theories of halohydrocarbon scavenger present in a given composition is equal to the number of mols of halohydrocarbon scavenger presentrnultiplied by o e-h t e um e of halog n atoms p m ec l for each gram atom of lead in the lead anti-detonant present. As applied to the anti-fouling compounds, the term theory designates the amount required to react stoichiometrically with the lead so that all of the lead atoms andall of the arsenic, antimony, or bismuth atoms could be in the form of Pb (ZO wherein Z is: an element such as arsenic, antimony or bismuth, that is, two atomic proportions of Z element for for each 3 atomic proportions of lead. Therefore a theory of the anti-fouling compound is one tool thereof multiplied by two-thirds (that is, twothirds of a mol of the anti-fouling compound), for each gram :atom of lead in the lead anti-detonant present, and therefore the number of theories of anti-fouling compound present in a given composition is equal to the number of mols of the anti-fouling compound present multiplied by three-halves, for each gram atom .of leadin the lead anti-detonant present.

While it is to be understood that thepresent compositions may be utilized in any leaded'gasoline fuel, the compositions are of particular importance with respect to use in reciprocating internal combustion engine gasoline fuels, and especially such aviation fuels. This is true because of the relatively more frequent occurrence of spark plug fouling in spark ignition aviation engines, with the greater inherent danger to human life in the case of failures of such engines. In addition to the lead anti-detonant and the scavenger compositions, the gasoline fuels, or the concentrates for addition thereto may also contain corrosion inhibitors and stabilizers, such as.2,4-dimethyl-6-tertiarybutylphenol and other alkyl phenols, N,N-dibutyl-p-phenylene diamine, hydroquinone, phenyl-alpha-naphthyl- 7 amine, N-butyl-p-aminophenol, alpha-naphthol, etc., dyes and the like.

By the term leaded gasoline, and the terms of similar import, is meant a petroleum fraction boiling in the gasoline hydrocarbon range (between about 50 F. and about 450 F.) to which has been added a small amount, usually between about 1 and about 6 cc. per gallon, of a metalloorganic, usually an organo-lead, anti-knock compound, such as a tetra-alkyl lead, e. g., tetra-ethyl lead, tetrai-propyl lead, etc.

The fuels to which the present scavenger compositions are added are preferably those which are relatively stable with respect to oxidation or gum formation. The stability may result from the use of stable base stocks such as aviation alkylate, straight run gasoline fractions, or other fractions which have been highly refined to remove olefins, or the stability may result from the use of oxidation stabilizers, such as those mentioned above. The term stable gasoline as used herein refers to gasoline fuels having a maximum of 5 mg. existent gum per 100 ml. of fuel (ASTM D-381-50), and a maximum of 10 mg. of gum per 100 ml. of gasoline after accelerated aging for 16 hours at 100 C. and 100 p. s. i. pressure. (The foregoing gum values apply to the fuel before addition of nonvolatile additives, such as the anti-fouling agents of the present invention.)

As indicated above, the scavenger compositions of this invention are particularly useful in aviation gasoline. By the term aviation gasoline is meant a relatively high grade of gasoline fuel used in aviation engines, as distinguished from the lower quality gasolines, or motor fuels used in automotive engines. Aviation fuels have a more clearly specified boiling range, generally running from a minimum of about 100 F. to a maximum of about 350 F. The anti-knock rating of such fuels is often appreciably higher than that of 100 octane number gasoline. Because of the demand for high quality, thermally cracked fractions are never used in aviation gasolines. Catalytically cracked fractions may sometimes be used, but only after treatment to remove olefins. One of the reasons for the restrictions upon incorporation of cracked gasolines in aviation fuels is that the oxidation stability of aviation fuels must be much greater than that required for motor fuels. For example, when tested according to a method such as described in the patent issued to Thomas W. Bartram, U. S. 2,256,187, an aviation fuel base stock will go well beyond 4 or 5 hours before the oxygen pressure will have decreased by 5 pounds per square inch.

The present application is a continuation-in-part of our copending application Serial No. 242,309, filed August 17, 1951, which is in turn a continuation of our application Serial No. 167,376, filed June 10, 1950, now abandoned.

We claim as our invention:

1. A fuel composition for internal combustion engines consisting essentially of a stable gasoline, a minor effec' tive anti-detonant amount of an organo-lead anti-detonant, and a scavenger mixture for said anti-detonant consisting essentially of a halohydrocarbon scavenger and a compound selected from the group consisting of hydrocarbyl-substituted-cycloalkyl hydrides, oxides and sulfides of an element of group VB of the periodic table having an atomic number from 33 to 83, inclusive, wherein said group V-B element is attached to an alicyclic ring through not more than one atom, said atom being a chalcogen atom, each cycloalkyl group hearing from 1 to 3 aliphatic hydrocarbyl substituents, said ha-lohydrocarbon scavenger and said group VB compound being present in amounts such that, where (a) is the number of mols of said halohydrocarbon scavenger present multiplied by one-half the number of halogen atoms per molecule, for each gram atom of lead in the lead anti-detonant present, and (b) is the number of mols of said group V-B compound present multiplied by three-halves, for each gram atom of lead in the lead anti-detonant present the total of (a) plus (11) is from about 0.4 to about 2.0, (b). is.

from about 0.01 to about 0.6, and the ratio of (a) to (b) is from about 3:2 to about :1.

2. A gasoline fuel additive composition consisting es sentially of an organo-lead anti-detonant and a scavenger mixture for said anti-detonant consisting essentially of a halohydrocarbon scavenger and a compound selected from the group consisting of hydrocarbyl-substitutedcycloalkyl hydrides, oxides and sulfides of an element of group V-B of the periodic table having an atomic number from 33 to 83, inclusive, wherein said group V-B element is attached to an alicyclic ring through not more than one atom, each cycloalkyl group hearing from 1 to 3 aliphatic hydrocarbyl substituents, said atom being a chalcogen atom, said halohydrocarbon scavenger and said group V-B compound being present in amounts such that, where (a) is the number of mols of said halohydrocarbon scavenger present multiplied by one-half the number of halogen atoms per molecule, for each gram atom of lead in the lead anti-detonant present, and (b) is the number of mols of said group V-B compound present multiplied by three-halves, for each gram atom of lead in the lead anti-detonant present, the total of (a) plus ([2) is from about 0.4 to about 2.0, (b) is from about 0.01 to about 0.6, and the ratio of (a) to (b) is from about 3:2 to about 100:1.

3. A lead scavenging composition for use with a leaded anti-detonant fuel for internal combustion engines consisting essentially of a halohydrocarbon scavenger and a compound selected from the group consisting of hydrocarbyl-substituted-cycloalkyl hydrides, oxides and sulfides of an element of group V-B of the periodic table having an atomic number from 33 to 83, inclusive, wherein said group V-B element is attached to an alicyclic ring through not more than one atom, each cycloalkyl group bearing from 1 to 3 aliphatic hydrocarbyl substituents, said atom being a chalcogen atom, said halohydrocarbon scavenger and said group V-B compound being present in amounts such that, where (a) is the number of mols of said halohydrocarbon scavenger present multiplied by one-half the number of halogen atoms per molecule, and (b) is the number of mols of said group V-B compound present multiplied by three-halves, the ratio of (a) to (b) is from about 3:2 to about 100:1.

4. A composition in accordance with claim 1, wherein the group V-B compound is a tri-hydrocarbyl-substituted cycloalkyl compound.

5. A composition in accordance with claim 1 wherein the group V-B element is arsenic.

6. A composition in accordance with claim 1 wherein the group V-B compound is a hydrocarbyl-substituted cycloalkylarsine.

7. A composition in accordance with claim 1 wherein the group VB compound is an alkyl-substituted-cycloalkylarsine.

8. A composition in accordance with claim 1 wherein the group V-B compound is an aryl-substituted-cycloalkylarsine.

9. A composition in accordance with claim 1 wherein the group V-B compound is tris(3,3,5-trimethylcycloheXyDarsine and the gasoline is an aviation gasoline boiling Within the range 100 F. and 350 F., contain, ing no thermally cracked gasoline fractions and no olefinic catalytically cracked gasoline fractions, and having a maximum of 5 mg. of existent gum per 100 ml. of gaso: line as determined by ASTM test D-381-50.

10. A composition in accordance with claim 1 wherein the group V-B compound is tris(3,3,5-trimethylcyclohexyl) arsenite.

11. A composition in accordance with claim 1 wherein the group V-B compound is tris(3,3,5-trimethylcyclohexyl) arsenate.

12. A composition in accordance with claim 1 where 9 in the group V-B compound is tris(3,3,5-trimethylcyclohexyl) stibine.

13. A composition in accordance with claim 1 wherein (b) is from about 0.05 to about 0.4.

14. A fuel composition for internal combustion engines consisting essentially of a stabilized automotive gasoline, a minor effective anti-detonant amount of tetraethyl lead, and a scavenger mixture for said tetraethyl lead consisting essentially of ethylene dibromide, ethylene dichloride and tris(3,3,S-trimethylcyclohexyl)arsine, said ethylene dibromide, ethylene dichloride and said tris(3,3,5-trimethylcyclohexyl)arsine being present in amounts such that where (a) is the total number of mols of ethylene dibromide and ethylene dichloride present for each mol of tetraethyl lead present, and (b) is the number of mols of tris(3,3,S-trimethylcyclohexyl)arsine present multiplied by three-halves, for each mol of tetraethyl lead present, the total of (a) plus (b) is from about 0.4 to about 2.0, (b) is from about 0.01 to about 0.6, and the ratio of (a) to (b) is from about 3:2 to about 100:1.

15. A fuel composition for internal combustion engines consisting essentially of a stable aviation gasoline boiling within the range 100 F. and 350 F., containing no thermally cracked gasoline fractions and no olefinic catalytically cracked gasoline fractions, and having a maximum of 5 mg. of existent gum per 100 ml. of gasoline as determined by ASTM test D-381-50, a minor efiective anti-detonant amount of tetraethyl lead, and a scavenger mixture for said tetraethyl lead consisting essen- References Cited in the file of this patent UNITED STATES PATENTS 1,592,955 Midgley July 20, 1926 1,766,819 Hartmann et al. June 24, 1930 1,988,176 Merrill Jan. 15, 1935 2,151,432 Lyons et al Mar. 21, 1939 2,396,258 Friedheim Mar. 12, 1946 2,477,220 Volz et al. July 26, 1949 OTHER REFERENCES Goddard: Text Book of Inorganic Chemistry, vol. XI, part II, pages 80, and 119 (1930).

Pascal et al.: Comptes Rendu, vol. 195, pages 14-16 (1932).

Dupere: Comptes Rendu, vol. (1942).

Beilstein: vol. XV/XVI4th ed., 2nd supplement (1951), pages 523, 574 and 597.

214, pages 82-84 

1. A FUEL COMPOSITION FOR INTERNAL COMBUSTION ENGINES CONSISTING ESSENTIALLY OF A STABLE GASOLINE, A MINOR EFFECTIVE ANTI-DETONANT AMOUNT OF AN ORGANO-LEAD ANTI-DETONANT, AND A SCAVENGER MIXTURE FOR SAID ANTI-DETONANT CONSISTING ESSENTIALLY OF A HALOHYDROCARBON SCAVENGER AND A COMPOUND SELECTED FROM THE GROUP CONSISTING OF HYDROCARBYL-SUBSTITUTED-CYCLOALKYL HYDRIDES, OXIDES AND SULFIDES OF AN ELEMENT OF GROUP V-B OF THE PERIODIC TABLE HAVING AN ATOMIC NUMBER FROM 33 TO 83, INCLUSIVE, WHEREIN SAID GROUP V-B ELEMENT IS ATTACHED TO AN ALICYCLIC RING THROUGH NOT MORE THAN ONE ATOM, SAID ATOM BEING A CHALCOGEN ATOM, EACH CYCLOALKYL GROUP BEARING FROM 1 TO 3 ALIPHATIC HYDROCARBYL SUBSTITUENTS, SAID HALOHYDROCARBON SCAVENGER AND SAID GROUP V-B COMPOUND BEING PRESENT IN AMOUNTS SUCH THAT, WHERE (A) IS THE NUMBER OF MOLS OF SAID HALOHYDROCARBON SCAVENGER PRESENT MULTIPLIED BY ONE-HALF THE NUMBER OF HALOGEN ATOMS PER MOLECULE, FOR EACH GRAM ATOM OF LEAD IN THE LEAD ANTI-DETONANT PRESENT, AND (B) IS THE NUMBER OF THE MOLS OF SAID GROUP V-B COMPOUND PRESENT MULTIPLIED BY THREE-HALVES, FOR EACH GRAM ATOM OF LEAD IN THE LEAD ANTI-DETONANT PRESENT, THE TOTAL OF (A) PLUS (B) IS FROM ABOUT 0.4 TO ABOUT 2.0, (B) IS FROM ABOUT 0.01 TO ABOUT 0.6, AND THE RATIO OF (A) TO (B) IS FROM ABOUT 3:2 TO ABOUT 100:1. 